Episodic memories, in contrast to semantic memories or beliefs, are distinguished by features that specify the circumstances of encoding, that is, the source of the memory (the what, where, when, who, and other features that make up an "event"). Uncertainty and conflict in episodic memory often revolves around the source of memories, e.g., "Did I mail the check or only think about mailing it?" "Did I hear that advice from my doctor or from my neighbor?" Disruption of source monitoring is a common consequence from normal aging and a frequent symptom (e.g., hallucinations and delusions) in psychotherapy, and a potential consequence of brain damage, especially in frontal areas. The source monitoring framework (SMF) characterizes the processes involving in encoding and remembering (and falsely remembering) episodic memories, and provides a theoretical approaches for understanding both normal and abnormal memory distortion. The present research has three goals: The first is to develop a formal model of the role of cognitive conflict and control in source monitoring, using a dynamical (Hopfield) neural net model. Results of behavioral studies in which participants make judgements about the source of previously presented items (e.g. was a word seen or heard?) Will be used to derived parameters of the model. The second goal is to further our understanding of the neural substrates of source monitoring. In particular, fMRI studies will be conducted to test the hypothesis that the anterior cingulate (ACC) is sensitive to cognitive conflict during episodic remembering, and that different regions of ACC detect conflict between features of memories and conflict between tasks (e.g., monitoring for multiple features of memories). Additionally hypothesis to be tested include that conflict, and thus ACC activity is modulated by the motivation to be accurate, the task relevance of potentially competing representations, and selective focus on a subset of information in memory. The third goal is to integrate the dynamical model of source monitoring. The long-range goal is to characterize the way in which ACC and other brain regions, particularly prefrontal cortex, interact during the retrieval and evaluation of memories, and the ways in which this memory monitoring system can be disrupted (e.g., by aging, injury, and disease).